Photogrammetry with brdf calculation?

[MANUEL_MOUSIOL]

Did anybody hear of or does know a way to combine photogrammetry with brdf calculation?
i would love to have something like dabarti tools but with photogrammetry functions...

[joconnell]

Tbh since brdf is a function of surface bumpiness / geometry and size, if you had a light with a measured surface area (radius of bulb, width / height of a softbox surface) you could make yourself a small measured setup where you shoot a sample object at a specific distance from that light, recreate the same size and distance in vray and then tweak your glossy settings til you get a similar spread of highlight.

[MANUEL_MOUSIOL]

That's an interesting approach. I was looking for a more automated method though

[joconnell]

I think we were looking at some kind of arduino / raspberry pi solution where a camera on a 90 degree rotating arm with a measured pen light would take photos every few degrees and compile a curve but again it might not be amazingly accurate, there was a recent siggraph paper where it used a camera phone and it's onboard flash to work out brdf but I'm personally not a coder or smart enough to make anything of it - there's nothing off the shelf that'd give you back a usable value in vray at the minute, you could look at something like a glossmeter for intensity and focus of highlight but again you'd have to do a bit of comparison between the measured results and a corresponding vray value

[MANUEL_MOUSIOL]

Yeah, a setup like that could work. Different light sources and different photogrammetric models, later use the textures of the objects in Dabarti capture to generate the maps.
not sure if the same photos with different lighting conditions lead to the same photogrammetric mesh though...
Sounds like a lot of work too haha

[^Lele^]

I think we were looking at some kind of arduino / raspberry pi solution where a camera on a 90 degree rotating arm with a measured pen light would take photos every few degrees and compile a curve but again it might not be amazingly accurate, there was a recent siggraph paper where it used a camera phone and it's onboard flash to work out brdf but I'm personally not a coder or smart enough to make anything of it - there's nothing off the shelf that'd give you back a usable value in vray at the minute, you could look at something like a glossmeter for intensity and focus of highlight but again you'd have to do a bit of comparison between the measured results and a corresponding vray value

Perilously close to how vrscans are done, eh. :P

[joconnell]

But you guys are way smarter than me and can actually implement it

[^Lele^]

But you guys are way smarter than me and can actually implement it

THEM guys, let's not get confused, here. XD

[joconnell]

You've a pretty impressive range of thoughts and theories too, they're lucky to have you